How to Grow Anchusa
'Blue Angel' from Seed
One of the most vivid, saturated blues you can grow from seed — clusters of gentian-indigo flowers that glow from June to September, drought-tolerant once established, and deeply attractive to bees
There are blues in the garden, and then there is the blue of Anchusa — a colour of such intensity and purity that it stops you in your tracks when you encounter it for the first time. Not the pale, washed-out blue of many garden flowers, and not the purple-tinted blue of lavender: this is a genuine, saturated, vivid indigo-blue, the colour of gentian and of a clear October sky, carried in massed clusters of small open-faced flowers on compact, bushy plants reaching 30–45cm. When a group of 'Blue Angel' plants is in full flower in midsummer, the colour is almost electric in its intensity.
Anchusa capensis 'Blue Angel' is technically a short-lived perennial — botanically Anchusa capensis is a biennial or tender perennial from South Africa — but it flowers so freely in its first year from seed, and it performs so well when treated as an annual or biennial in UK conditions, that most gardeners grow it this way. It is fast-growing, compact, genuinely easy, drought-tolerant once established, and one of the best blue-flowering plants available from seed for the front of a sunny border. The nectar-rich flowers attract bees and butterflies in abundance.
Quick Facts at a Glance
Plant Type
Hardy Annual (grown as)
Sowing Time
Feb–Apr indoors · Apr–May direct
Flowering Months
June – September
Position
Full sun; well-drained
Height & Spread
30–45cm · 30cm
Difficulty Rating
2 out of 5 — Easy
Understanding the Plant
Anchusa capensis 'Blue Angel' belongs to the Boraginaceae family — the same family as borage, forget-me-not, comfrey and pulmonaria — which explains both the characteristic blue flower colour and the coarse, bristly foliage typical of the family. It originates from the Cape region of South Africa, which accounts for its excellent drought tolerance and its preference for free-draining, sunny conditions.
The flowers are produced in dense, branching clusters — typical cymes of the borage family — each individual flower small but the collective effect of dozens of them simultaneously open on a compact plant being one of considerable impact. The deep blue pigmentation is one of the most intense available in annual-grown cottage garden plants, and because the flowers are held on compact, self-supporting plants, 'Blue Angel' works particularly well at the front of borders where taller, more architectural plants would obscure neighbouring plants.
The Rarest Colour in the Garden
True blue is genuinely rare among flowering plants — most flowers described as blue are actually violet, mauve, or purple. The blue of Anchusa 'Blue Angel' is one of the few that delivers the real thing: a clear, vivid, pure blue with minimal purple or red undertones. This makes it extraordinarily valuable in the border for colour combinations — it provides the cool, clear contrast that most supposed blues cannot. Plant it alongside yellow rudbeckia, orange calendula or warm red roses and the effect is electric.
Annual or Perennial?
Botanically, Anchusa capensis is a short-lived perennial, but in UK conditions it performs most reliably and most vigorously when treated as a hardy annual — sown each spring for summer flowering, or sometimes as a biennial, sown in summer for the following year's display. Plants that survive the winter in mild, free-draining conditions may produce a second season, but first-year performance from a spring sowing is usually the most impressive. Save seed freely — it germinates reliably the following year.
When & How to Sow
Anchusa 'Blue Angel' is straightforward to germinate — it requires light, adequate warmth, and consistent moisture. The seed is larger than many annuals and somewhat easier to handle as a result. Germination can be a little slow and variable, but patience is rewarded.
Sowing Options
February to April indoors at 20°C — the recommended approach for flowers from June or July onwards. April to May direct outdoors — perfectly viable once soil has warmed; thin to 30cm apart. Anchusa can also be sown directly into flowering position in spring at around 1cm depth, thinning once seedlings are established. All approaches produce good results; the indoor sowing gives earlier flowers and more control.
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Sow into pots or modules of seed compost at 20°C. Surface sow and press lightly — do not bury deeply, as light aids germination. A light covering of fine grit or vermiculite (2–3mm) is permissible. Avoid full covering with compost.
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Keep consistently moist and maintain warmth. Germination takes 14–21 days at 20°C and can be somewhat variable. Some seeds may germinate much later — do not discard modules or pots too early. Keep compost evenly moist throughout; dry spells during germination reduce the rate significantly.
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Prick out once seedlings have two true leaves. Handle by the leaf. Pot into individual 7cm pots in standard potting compost. Grow on in good light — Anchusa does not like being drawn in poor light and becomes leggy if kept in dim conditions after germination.
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Harden off and plant out from late April. Anchusa is reasonably cold-tolerant and can go out earlier than frost-tender annuals — from late April in most UK locations with light overnight protection if needed. Space 30cm apart in full sun and well-drained soil.
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Cut back after the first flush. When flowering slows in midsummer, cutting plants back by around one-third stimulates fresh growth and a second flush of vivid blue flowers extending the season into September. This is one of the most effective techniques for getting good value from a compact anchusa planting.
Growing On Tips
Full Sun for Best Blue
The intense gentian-blue colour is most vivid in full sun. In partial shade the plants flower less abundantly and the colour appears less saturated. A south or west-facing border provides ideal conditions — anchusa originates from sunny, open South African habitats and thrives in the warmth and light.
Drainage is Key
Well-drained soil is essential — anchusa is notably intolerant of waterlogged conditions, particularly in winter. In heavy clay, work in grit or coarse sand before planting, or grow in raised beds. In naturally free-draining soil it requires minimal attention. The taproot dislikes sitting in wet conditions at any time of year.
Drought Tolerance
Once established, anchusa is genuinely drought-tolerant — the taproot reaches down to moisture that surface-rooted plants cannot access. Water young plants in their first few weeks; thereafter reduce watering and allow the soil to dry between waterings. Overwatering is more likely to cause problems than drought in established plants.
Cut Back for a Second Flush
Cutting back by one-third when the first flush of flowers fades in midsummer is the single most effective technique for extending the Anchusa season. New growth appears within one to two weeks and the second flush of flowers, while sometimes slightly less abundant than the first, continues into September. Without cutting back, plants often decline rapidly after their first peak.
Self-Seeding
Anchusa self-seeds readily in free-draining, sunny conditions. In a warm, sheltered garden it can become a reliable self-sower, with seedlings appearing around the parent plants in spring. These can be allowed to grow on in situ or transplanted when small, before the taproot becomes too large to move without damage.
Pollinator Value
The nectar-rich flowers of anchusa are particularly attractive to bumblebees, honeybees, solitary bees and butterflies. The open, accessible flower structure provides easy feeding for a wide range of pollinators, making it a genuinely valuable wildlife plant as well as a beautiful border annual. A group of flowering plants in full summer sun will be consistently busy with bees.
Common Problems & How to Fix Them
| Problem | Likely Cause | What to Do |
|---|---|---|
| Slow or uneven germination | Temperature variation or old seed | Anchusa germination is naturally somewhat variable — 14–21 days is typical but some seeds may take considerably longer. Maintain consistent warmth at 20°C. Do not give up on modules that appear empty — late germinating seeds often produce perfectly good plants. Use fresh seed for the best germination rates. |
| Plants become leggy | Insufficient light after germination | Move to the brightest available position immediately after germination. On a windowsill, rotate pots daily to prevent one-sided growth. If plants are drawn before transplanting, pinch back the growing tip to encourage bushier growth from lower nodes. |
| Colour less intense than expected | Insufficient sun or waterlogged soil | Anchusa's blue is at its most saturated in full sun and lean, well-drained conditions. In shade or wet soil the colour becomes significantly less vivid. Relocate to a sunnier, better-drained position if possible. |
| Powdery mildew | Dry at roots, poor airflow, warm days and cool nights | Water at the base of the plant. Improve airflow through correct spacing (30cm). Remove affected leaves. Cutting back as the first flush fades often removes most mildew-affected growth and the new flush is typically clean. Most common in late summer. |
| Short season — plant declines after flowering | Natural behaviour without cutting back | Cut back promptly when flowering slows to stimulate a second flush. Without this intervention, anchusa tends to put its energy into seed production and declines quickly after its first peak. Regular deadheading also helps — remove spent flower clusters before seed sets. |
When to Expect Flowers
From a February or March indoor sowing, Anchusa 'Blue Angel' typically comes into flower in June or early July. The first flush is the most abundant and most visually impactful — plants covered in vivid blue clusters from every branch simultaneously. After the midsummer cut-back, the second flush follows in August and September. From an April direct sowing, flowers begin in July and continue, with the cut-back, into October in mild autumns.
Sow indoors from February or direct in spring — first flowers in June or July, with a second flush into September after the midsummer cut-back.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
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| 🌱 Sow Indoors |
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| 🪴 Plant Out |
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| 💙 Flowering |
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Plant Specifications
The most vivid blue you can grow from seed
If you have been searching for a true, vivid, saturated blue for a sunny summer border — not the violet-tinged purple that most supposed blue flowers actually produce, but a genuine, clear, gentian-indigo blue — Anchusa 'Blue Angel' is the answer. It is easy to grow, compact, drought-tolerant, genuinely attractive to bees, and produces a colour that will stop you in your tracks every time you walk past it. Sow in February, cut back in midsummer for a second flush, and let the blue do what few other garden plants can manage so effectively.
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